pg_index

pg_index

The pg_index system catalog table contains part of the information about
indexes. The rest is mostly in pg_class.

Table 1. pg_catalog.pg_index

column

type

references

description

indexrelid

oid

pg_class.oid

The OID of the pg_class entry for this index.

indrelid

oid

pg_class.oid

The OID of the pg_class entry for the table this index is
for.

indnatts

int2

The number of columns in the index (duplicates
pg_class.relnatts).

indisunique

boolean

If true, this is a unique index.

indisprimary

boolean

If true, this index represents the primary key of the table.
(indisunique should always be true when this is true.)

indisexclusion

boolean

If true, this index supports an exclusion constraint

indimmediate

boolean

If true, the uniqueness check is enforced immediately on insertion (irrelevant if
indisunique is not true)

indisclustered

boolean

If true, the table was last clustered on this index via the
CLUSTER command.

indisvalid

boolean

If true, the index is currently valid for queries. False means the
index is possibly incomplete: it must still be modified by
INSERT/UPDATE operations, but it cannot safely be
used for queries.

indcheckxmin

boolean

If true, queries must not use the index until the xmin of this
pg_index row is below their TransactionXmin event
horizon, because the table may contain broken HOT chains with incompatible rows that
they can see

indisready

boolean

If true, the index is currently ready for inserts. False means the index must be
ignored by INSERT/UPDATE operations

indislive

boolean

If false, the index is in process of being dropped, and should be ignored for all
purposes

indisreplident

boolean

If true this index has been chosen as "replica identity" using ALTER
TABLE ... REPLICA IDENTITY USING INDEX ...

indkey

int2vector

pg_attribute.attnum

This is an array of indnatts values that indicate
which table columns this index indexes. For example a value of 1 3 would mean that the
first and the third table columns make up the index key. A zero in this array
indicates that the corresponding index attribute is an expression over the table
columns, rather than a simple column reference.

indcollation

oidvector

For each column in the index key, this contains the OID of the collation to use
for the index.

indclass

oidvector

pg_opclass.oid

For each column in the index key this contains the OID of the
operator class to use.

indoption

int2vector

This is an array of indnatts values that store per-column flag
bits. The meaning of the bits is defined by the index's access method.

indexprs

text

Expression trees (in nodeToString()
representation) for index attributes that are not simple column references. This is a
list with one element for each zero entry in indkey. NULL if all index attributes are
simple references.